Cyclic Data; Status Byte - Siemens sitrans LR200 Instruction Manual

Cyclic Data

When you configure SITRANS LR200 on the PROFIBUS PA bus, there are two slots
available for modules.
Each of the slots has to have a module defined in it.
Note:
Slot 0 always transmits AIFB1 information
changed to AIFB2 information. If you do not wish to have data transmitted, then you must
use a Free Place module in that slot.
Each of the two Analog Input Function Blocks can be set up to return Level, Distance, or
Volume. Within the function blocks, the values are scaled according to the user
requirements (please see
AIFB1 and AIFB2 return 5 bytes of data each:
AIFB1 byte 1
AIFB2 byte 6
The first 4 bytes are the floating point representation (IEEE) of the variable. The variables
are the outputs of the function block. The 5th byte is the status word and the list of
possible values is given in the chart below.
The 5 bytes must be read consistently, in a contiguous chunk: they cannot be read byte by
byte, and cannot suffer an interrupt. If you are using an S7-300 / 400, you will need to use
SFC14 DPRD_DAT: Read Consistent Data of a Standard DP Slave.

Status Byte

In PROFIBUS PA there are two possible types of status byte:
• status byte: originally defined in Profile Standard V3.0
• condensed status: an alternative status byte defined in Profile Standard V3.01
You can choose which type of status byte will be returned, by enabling or disabling
Condensed Status Mode (3.6. 1 .). The default setting is Condensed Status disabled: Status
Byte will be returned, and the following codes will be used.
1)
For more information, please see
page 125.
7ML19985JR01 SITRANS LR200 (PROFIBUS PA) – INSTRUCTION MANUAL
1)
; slot 1 defaults to Free Place, but can be
Analog Input Function Blocks 1 and 2
Floating Point
byte 2 byte 3
byte 7 byte 8
Analog Input Function Blocks 1 and 2
on page 125 for details).
Status
byte 4 byte 5
byte 9 byte10 byte10
on
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